Automatic safety latches



Feb. 2, 1960 w. A. HERPICH ETAL 2,923,424

AUTOMATIC SAFETY LAToHEs 2 Sheets-Sheet 1 Filed Jan. 9, 1957 /VENTORS w m... ATTORNEYS Feb. 2, 1960 w. A. HERPICH ETAL 2,923,424

AUTOMATIC SAFETY LATcHEs 2 Sheets-Sheet 2 Filed Jan. 9, 1957 INVENTORS BY mali-...T

ATTORNEYS' United States Patent AUTOMATIC SAFETY LATCHES William A. Herpich and Neil Wender, Knoxville, Tenn., assignors to Dempster Brothers, Inc., Knoxville, Tenn., a corporation of Tennessee Application January 9, 1957, Serial No. 633,236

8 Claims. (Cl. 214-317) This invention relates to improvements in automatic safety latches for use on dumping hooks of transporting and dumping equipment, such as that disclosed in the patent of George R. Dempster, et al., No. 2,751,100,

June 19, 1956.

In such transporting and dumping equipment, a container is raised by a hoisting unit on a skid frame and is provided with a bail connected with the container for engagement with an automatic hook on the skid frame to facilitate dumping of the container either by tipping over the container bodily or lowering the drop bottom door with respect thereto. Frequently, the containers are loaded improperly or the load is centered toward one side or the other, and in either event, shifting of the container may occur on the skid frame during the dumping operation. As a result of such shifting of the container or its tipping over, accidentally or otherwise, the bail may be lifted out of the dumping hook before the operator is ready for disengagement of the lcontainer therefrom. Inasmuch as the container is often dumped in a high position, this may result in serious damage to equipment or injury to operators or others.

Automatic safety hooks have been proposed heretofore, but these have not proven entirely satisfactory for all types of containers, especially for tilt-type containers when handled on transporting and dumping equipment of the character set forth in the aforesaid Dempster patent, No. 2,751,100, in which the hook is mounted on a telescopic section of the skid frame for upward and downward movement with respect thereto.

One object of this invention is to overcome the foregoing objections by providing a safety latch which will insure of fastening the bail in the hook when the telescopic section is raised for dumping of the container.

Another object of the invention is to improve the construction of the automatic hook of a hoisting and dumping unit by providing a safety latch on the movable telescopic section on which the hook is mounted, to retain the container bail effectively in the hook during dumping of the container.

Still another object of the invention is to provide an automatic safety latch which is operated during raising movement of the telescopic section on which the hook is mounted, and thereby to insure of positive and effective retaining of the bail of the container in the hook throughout the dumping operation and to release `the safety latch automatically upon lowering of the telescopic section following the dumping action.

These objects may be accomplished, according to one embodiment of this invention, by providing a safety latch on the telescopic section of the transporting and dumping equipment vadjacent the dumping hook, in position for engaging o-ver the bail of the container in the hook. The latch is pivotally mounted on a fulcrum bracket on the telescopic section and is provided with a counterweight extending downwardly to the lower end of the telescopic section, to be actuated upon lowering of the telescopic section by abutment againsta connected por- "lee tion of the carriage.

This embodiment is illustrated in the accompanying drawings, in which:

Fig. 1 is a vertical sectional view, partly in elevation, through the telescopic section of the equipment;

Fig. 2 is a rear elevation thereof;

Fig. 3 is a disassembled perspective view of the auto! matic safety latch assembly;

Fig. 4 is a bottom plan view, partly in section, of th telescopic section frameV structure, on the line 4-4 in Fig. l; and

Fig. 5 is an elevational view of a skid frame assembly to which the invention may be applied.

The invention is shown as applied to transporting and dumping equipment of the type set forth in the aforesaid Dempster et al. patent, No. 2,751,100. Such equipment includes a carriage C (Fig. 5) mounted on a vehicle, provided with an elevator E and skid frame-structure upon which a container is to be elevated for transportation and for dumping. The container is usually provided with a bail B (Fig. 1) for engaging and holding the container` on the transporting equipment during dumping. The bail is usually engaged by an automatic hook, one or more of which hooks may be mounted on a telescopic section 1 of the elevator E on the carriage C as set forth in said patent.

In the present embodiment of the invention, this is illustrated as applied to the telescopic section of transporting equipment of the character described, although it is recognized to be applicable to many other types of transporting equipment and is not to be restricted to the specic form set forth in the aforesaid Dempster et al.

patent, No. 2,751,100, nor even to that type of equipment.

The telescopic section 1 comprises a rectangular frame structure, generally indicated at 2, adapted to be mounted within the frame of the carriage or within the elevator structure E provided thereon, according to the example shown in the aforesaid Dempster et al. patent, No. 2,751,100. Mounted within the frame 2 are hookY guide angle bars 3 spaced apart transversely, as shown in Fig. 2, to receive and mount one or more automatic hooks 4 therein. Two such hooks are illustrated at 4, spaced apart vertically of the length of the telescopic section 1.

of automatic hooks illustrated is substantially the samev as set forth in the Dempster patent, No. 2,404,830, July 30, 1946.

The telescopic section 1 may be moved upward and downward relative'to the elevator E, by one or more hydraulic cylinders 7 connected therewith.

When dumping some types of the containers, such, for example, as the tilt-type container, with dumping equipment in which the telescopic section carries the hook or hooks and is moved upward with` respect to the carriage, `it has been found that the bail will occasionally come out of the dumping hook too soonP The counterweight will assure of, Vclosing of the safety latch over the bail in the hook .l 'ansa-1.2m j;

-We have provided a .safety...latch.generally.indicated at 8, extending upward on each opposite side of the hook 4Vand having a downwardly turned hook portion 9 arra'rgeidfiin` opposedurelationztozth throatrof the tantos* 8 :on: opposite sides of the, hookf 4 vextend downwardly from' the lowerendportion of thelautomatic hook Lrand are-pivotally -supported vat their flower ends within .Ithe

telescopic'section and mounted thereon. f

InZ this embodiment of the invention,- .themfpivotal mountingmeans for the latchesifcomp'risesya crossrod.

o1',l pivotbolt 9 extending throughasleeve 10, whiehamayi, benw'elded or"v otherwise `secured rri'gidly'Y to;thef:latches r8 onbeinterposed therebetween 3fo`r1 holdingnthes'e properly spaced apart. The bolt 9 extends looselyavthroughthe sleevle :10 zsoas to form .-,a journal.;supportvthereforvarid for the latches:8.'j.Y

The oppositeends of:therbo1t'119earesnnnunted fulcnim -1 bracket L assembly s including :arfpir cof upright bars 11 supported on oppositefendsfof;anliangle 'ibarll .-n

The' angle.v bar, 12 is .,insabuttingirrelationawithtme .back

ed'gesol?` thefspacedcbars'. iThetba'. lzisabrace'clr-by. horizontally extending bars 13 that encompass ithe, inside.

1egs'.of the. hook guide 'anglebars 3. Thesepartsmay be welded or otherwise secured rigidly vtogether,,zand'1 serve to provide a1secure and etective mounting; forzitlie lat-ches 8.

.Extending downwardly Afrom therrespectiveflatchesf8 t arerods 14 which form eounterweights'for` therespective;` Each of ther rods f14- isf: connected;-wi'thvtherad@ latches.

jacent latch' 8 by'a clevis'15 andpin 161pivotal1y con necting the cleviswith thelatch.

At their lower ends, the counterweight `rods R14-:ex-

tenddownward through guide sleeves-17 secured to-.theW lower end `of the telescopic section .1.` The rods-..14` should extend throughlthe s1eevesf17A when the 1atche`s.8

areclosedgoverathe throat `of the hook,; as illustra-tedfin4 Fig. 1. The extreme end ofgeach rod T iseprovided Witha hole 18 therein, Vadapted to receive a; pin L-19 normally retained Ain-1a-holder20 on the frame 2,but capable' ofbeing disengaged therefrom and being. inserted; into the hole.18 when it is kdesiredto retaintthef 1atch-8in an inoperative position.

`-bail against acciderltallV release from the throatof lthe hook during the dumping action. The hook portion 9 on the latch 8, acting under the inuence of each rod 14, will be suicient to insure of retaining the bailin the hook, *so long as the telescopic section 1 is in raised t position with respect tothe elevator and the carriage.

After the dumpingactionhas been completed, the telescopic section A3111's4 lowered; iny e the carriageto its lowermost position (Fig. 5). When it reaches such lowermo'stpositi'n,thetlowerlerds ofthe rods 14vabut against across member' "onathe `carriage `and thereby raise the rods to swing the latches'S ontheirpivotboltl,to retracted positi'onsfaway F from 3: the; throat@y ot theA Shook 4, thereby disengagyingthe baiLB and releasing it for separation from the'auto'ratic hook.

Thisrprovides an etective automatic safety latch for retaining the bail in the automatic hook whenever the vtelescopic `:sectionl` is .i raiseddurling `.theldumping: action.

Not all types of containers will requiregthe use of; the Y safetylatches 8. When these-are not;nee'ded,.they` may releasedy positions, which will raise the-rodsltsuiciently to.exposetheA holes 18 above thesleeves 17.` ,Uponin-s sertionof-the pins 19 in the `holes abovethe 'sleeves.17,

the-latches'zs -will beheld intheir retracted;positions,= When theglatchesbare" neededfhowever, the latter are operated inaresponse'tol.

where `they will be ineffective.

l'ilflrweightfof the rods 14 s liding-vvertically-in theljsleeve` When their telescopicV sectionfl, is lowered 'to its.l lower;

mostvpositionin` the elevator E (Fig. 5) during; the nor mal operation of the transporting and` dumping equipment,,the lower ends' of the counterweightrods..14flwi1lengage across. member on theelevatorE in. the carriage C, and therebypush the.'V rods upward, Vautomatically-fre` t 145 be rendered lneiectlve by being moved back to their;`

tracting theY latches Stoutrof theV pathfof theJbailB tot" the -co'ntainent This is the positionofthe 'telescopic sectionzsduring,engagement of the container by-'the hook-y It tunpotionssautomatically without requiringaanyjpower meansttobee connected,-therewitha{responding-.onlyf tos the f position aofi thee. telescopicesectierr `with lrespect tot` thecarriage, and is released automatically when `thezitelpesccipic Yrsection-isreturnedto -its3normalposition l 'Ihecon'struetijonQis :extremely/simple andg. does. not

be added thereto;atglittlefexpense.` Nevertheless, .it achievessa material safetyffactonthat. is important` in the eiective-.handling andldumpinglolcontainers on-this type of equipment.

Y .While .the invention has been `illiilstrated and. described in ione ernbodivrnlent,.it is :recogfnized;` thatwariations `and without departing from changes .mayz beV Amade .therei the invention; assetforthin the=cla`ims- We. claim: I t

l; In transporting..equipmenofthe character .described l having` .anfuprzight skid. frame'. forfmovement of a` con-g tainer therealonglwitla bailfongthecontainer, the com bination of askid frame section.having a hook thereonin` position torreceive 'the ,bailtandto retainthe container-` on theeskid frame for` dur'npirig,ra..safety; laten;v having. a hook portionnin overlapping relationlwiththehook, means"` mounting` the. safety latch; .on .the skid. frame` sectionfor movement. to". operative Sand: Ji'noperaitve`V positionswithi respect'. to;th'hooktlcounterweightrneans.connected with the safety. .latcharand extending downwardly therefrom t normallyltending tofrnovetthelatcli. toen operative lpol sitin over the hookpandhrneansffor'imparting a, .pushing.`

` action `torthe,counterweightrneansgforf .opening4 the safety ansportlng equxpme ty 'of-M 'thef` character. deingf. an -fuprj'ghtfsleidsframcz for: movementA4 olf` aI edntalne'r.-herealon'gf,with`.af. bail` Aon; the container, the combinationfpfatskidiframesectiomhavingla hookthere tai1"1e1 .onthe".s ,'d'ffrarneforr dumping, .a `safety `latchllavl iu'g-` aholi` portion in overlapping'relationrwith the" hook, mas'mounting 'the safety latchonjfthesection formovement 4topoperative and ,inoperativeL positions. with'respect to e the hook, and. a .counterlwei'ghtf rod .connected with. thesafetyl latch and. extending. 'downwadlyg'therefrom for` tivepos'ition over. thehook:1

, 3. InA Ltransporting -equipment of the `.chairacter- `clescribed ,having an, `I Jprightskid. framey for; movementlo a container therealongwithra bailfon-fthescontainer," ther combination .offaskidefrarne section having fa 4houle-thereon in position to; receive the; bailanjdatol retain` the confV tain ionrthefslidiramefondumpinsaa safeux;latclrhaw:` inge heolcrpnrftioninverlapaine relation withnthefhookf mensmbunting: the; safety. latch-.onrthe'vsectiongforrmovement-fl togeoperatiwfandr-inoperative; positions With respect" toathefhookl-.ffdrrretininggand releasingcethezbailwith re':

t thretogaan accounterweightrrod:operativelyscom nectd withethe latchi andfextendingfIdownwardlyi to2 lowrtrfendaet:thensection-aforxioperatingttheolatchpsaid counterweight rod having an end portion projecting at said lower end of the section in position for engagement by a fixed abutment on the skid frame when the section is moved downwardly, to disengage the safety latch from the bail.

4. In transporting equipment of the character described having an upright skid frame for movement of a container therealong with a bail on the container, the combination of a skid frame section having a hook thereon in position to receive the bail and to retain the container on the skid frame for dumping, a safety latch having a hook portion in overlapping relation with the hook, means pivotally mounting the safety latch on the skid frame section for movement to operative and inoperative positions with respect to the hook for retaining and releasing the bail relative thereto, a counterweight rod pivotally connected with the safety latch and extending downwardly therefrom through the lower end portion of the section with a projecting lower end in position to be engaged by a fixed abutment on the skid frame to release the latch from its operative position over the bail.

5. In transporting equipment of the character described having an upright skid frame for movement of a container therealong with a bail on the container, the combination of a skid frame section having a hook thereon in position to receive the bail and to retain the container on the skid frame for dumping, a safety latch having a hook portion in overlapping relation with the hook, a fulcrum bracket mounted on the section, means pivotally mounting the lower end portion of the safety hook on the fulcrum bracket, and a counterweight rod pivotally connected with the lower end portion of the safety latch and extending downwardly through the lower end portion of the skid frame section, said counterweight rod having the lower end thereof projecting from the lower end of the section in position for engagement by an abutment when the section is moved to its lowermost position.

6. In transporting equipment of the character described, a skid frame section, an automatic hook mounted in the skid frame section in position to engage a portion of a container, a pair of safety latches on opposite sides of the hook, means pivotally mounting the safety latches on the section for swinging movement to operative and inoperative positions with respect to the hook, counterweight means connected with the safety latches lnormally tending to move said latches to operative positions, and means for imparting a pushing action to the counterweight means for opening the safety latch relative to the hook.

7. In transporting equipment of the character described, a skid frame section, an automatic hook mounted in the skid frame section in position to engage a portion of a container, a pair of safety latches on opposite sides of the hook, means pivotally mounting the safety latches on the section for swinging movement to operative and inoperative positions with respect to the hook, and counterweight rods connected with the safety latches and extending downwardly through the lower end portion of the section with the lower ends of said rods projecting therefrom for operative engagement to release the safety latches.

8. In transporting equipment of the character described having an upright skid frame for movement of a container therealong with a bail on the container, the combination of a skid frame section having a hook thereon in position to receive the bail and to retain the container on the skid frame for dumping, a safety latch having a hook portion in overlapping relation with the hook, means pivotally mounting the safety latch on the skid frame section about an axis located appreciably below the hook for swinging movement to operative and inoperative positions with respect to the hook, and counterweight means connected with the safety latch normally tending to move the latch to a locked position over the hook and holding the same locked relative thereto against removal by lifting of the bail in the hook, said counterweight means extending downwardly through the lower end of the skid frame section for engagement from below said section when said section reaches an extreme lowered position.

References Cited in the file of this patent UNITED STATES PATENTS 2,325,568 Eaton July 27, 1943 2,729,496 Jones Jan. 3, 1956 

